Analytical studies on the kavain metabolism in human specimens and liver cell lines [Elektronische Ressource] / vorgelegt von Fuad Ali Tarbah

Analytical studies on the kavain metabolism in human specimens and liver cell lines [Elektronische Ressource] / vorgelegt von Fuad Ali Tarbah

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Analytical studies on the kavain metabolism in human specimen and liver cell lines Inaugural-Dissertation zur Erlangung des Doktorgrades der Mathematisch-Naturwissenschaftlichen Fakultät der Heinrich-Heine-Universität Düsseldorf Vorgelegt von Fuad Ali Tarbah aus Derna, Libyen Düsseldorf 2003 Gedruckt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakultät der Heinrich-Heine-Universität Düsseldorf Referent: Prof. Dr. Th. Daldrup Korreferent: Prof. Dr. G. Willuhn, Prof. Dr. H. Weber Tag der mündlichen Prüfung: 17. 12. 2003 Parts of this Ph.D. Thesis have already been presented and/or published in: Tarbah F. A., Mahler H., Temme O. and Daldrup Th. Mass spectral characterisation of hepatic cell metabolites of D,L-kavain using HPLC and GC/MS systems. Special thissue: 37 TIAFT triennial meeting “Problems of Forensic Sciences” XLII: 173-180 (1999) Tarbah F. A., Mahler H., Temme O. and Daldrup Th. Determination of D,L-kavain and its metabolites in blood, serum and urine. Rapid quantitative method using fluid/fluid extraction and gas chromatography/mass spectrometry (GC/MS). Poster in 79. Jahrestagung der Deutschen Gesellschaft für Rechtsmedizin, Medizinische Einrichtungen der Universität / Gesamthochschule Essen (2000) Tarbah F., Mahler H., Kardel B., Weinmann W., Hafner D. and Daldrup Th. Kinetics of kavain and its metabolites after oral application. J. Chromatogr.

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Analytical studies on the kavain metabolism in
human specimen and liver cell lines






Inaugural-Dissertation
zur
Erlangung des Doktorgrades der
Mathematisch-Naturwissenschaftlichen Fakultät
der Heinrich-Heine-Universität Düsseldorf




Vorgelegt von
Fuad Ali Tarbah
aus Derna, Libyen



Düsseldorf
2003




















Gedruckt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakultät der
Heinrich-Heine-Universität Düsseldorf


Referent: Prof. Dr. Th. Daldrup
Korreferent: Prof. Dr. G. Willuhn, Prof. Dr. H. Weber
Tag der mündlichen Prüfung: 17. 12. 2003
Parts of this Ph.D. Thesis have already been presented and/or published in:

Tarbah F. A., Mahler H., Temme O. and Daldrup Th. Mass spectral characterisation
of hepatic cell metabolites of D,L-kavain using HPLC and GC/MS systems. Special
thissue: 37 TIAFT triennial meeting “Problems of Forensic Sciences” XLII: 173-180
(1999)

Tarbah F. A., Mahler H., Temme O. and Daldrup Th. Determination of D,L-kavain and
its metabolites in blood, serum and urine. Rapid quantitative method using fluid/fluid
extraction and gas chromatography/mass spectrometry (GC/MS). Poster in 79.
Jahrestagung der Deutschen Gesellschaft für Rechtsmedizin, Medizinische
Einrichtungen der Universität / Gesamthochschule Essen (2000)

Tarbah F., Mahler H., Kardel B., Weinmann W., Hafner D. and Daldrup Th. Kinetics
of kavain and its metabolites after oral application. J. Chromatogr. B 789 (1): 115-130
(2003)

Cabalion P., Barguil Y., Duhet D., Mandeau A., Warter S., Russmann S., Tarbah F.
and Daldrup Th. Kava in modern therapeutic uses: to a better evaluation of the
thbenefit/risk relation. Researches in New Caledonia and in Futuna (Draft). 5
th thEuropean Symposium of Ethnopharmacology, Valencia, Spain, 8 -10 May 2003





















To my parents, my wife and my children



Contents
1 INTRODUCTION 1
1.1 KAVA-KAVA HISTORY 1
1.2 RECREATIONAL USE OF KAVA BEVERAGES
1.3 MEDICINAL USE OF KAVA 2
1.4 CHEMISTRY OF KAVA-KAVA RHIZOMES 3
1.5 COMPOUNDS ISOLATED FROM THE KAVA ROOTS AND RHIZOMES 4
1.5.1 KAVALACTONES OR KAVAPYRONES
1.5.2 KAVA ALKALOIDS 6
1.5.3 CHALCONES AND FLAVANONES 7
1.6 SYNTHETIC KAVAIN
1.7 PHARMACOLOGICAL PROPERTIES OF KAVA, KAVAIN AND OTHER KAVA LACTONES 8
1.8 MECHANISMS OF ACTION 9
1.9 CLINICAL STUDIES 10
1.10 TOXICOLOGICAL PROPERTIES OF KAVA, KAVAIN AND OTHER KAVA LACTONES 10
1.10.1 KAVA DERMOPATHY
1.10.2 OTHER TOXICOLOGICAL EFFECTS OF HEAVY KAVA USAGE 11
1.10.3 TOXICOLOGICAL STUDIES OF D,L-KAVAIN ON ANIMALS 12
1.11 KAVA LACTONES METABOLISM AFTER CONSUMPTION OF KAVA EXTRACTS
1.12 KAVAIN METABOLISM AFTER CONSUMPTION OF SYNTHETIC D,L-KAVAIN 16
1.13 AIM OF THE STUDY 17
2 EXPERIMENTAL 18
2.1 PREPARATION OF HEP-G2-CELLS FOR THE KAVAIN METABOLISM STUDY 18
2.1.1 MATERIALS AND CHEMICALS 18
2.1.2 BUFFERS 18
2.1.3 ORIGIN AND DESCRIPTION OF THE HEP-G2-CELLS 19
2.1.4 PRODUCTION OF THE CULTURE MEDIUM 20
2.1.5 ASEPTIC TECHNIQUE FOR THE PREPARATION OF HEP-G2 CELL CULTURES 20
2.1.6 CELL HARVEST FOR BREEDING WITH KAVAIN ENDOWED CULTURE MEDIUM
2.2 INCUBATION OF KAVAIN WITH HEP-G2 CELL CULTURES 21
2.3 EXTRACTION PROCEDURES 22
2.3.1 FLUID-FLUID EXTRACTION
2.3.2 SOLID-PHASE EXTRACTION (SPE) USING BOND ELUTE C18 COLUMN 22
2.4 DERIVATISATION OF KAVAIN METABOLITES 22
2.4.1 METHYLATION
2.4.2 SILYLATION 23
2.5 GC/EI MS-METHOD FOR THE DETECTION AND IDENTIFICATION OF KAVAIN AND ITS
METABOLITES 23
2.6 PHYSICAL AND SPECTROGRAPHIC DATA OF THE REFERENCE SUBSTANCES AND THE
DETECTED METABOLITES 24
2.6.1 GC/EI MS DATA BASE OF KAVAIN AND ITS METABOLITES AS REFERENCE SUBSTANCES 24
2.6.2 EI-MS DATA OF KAVAIN METABOLITES FROM THE LITERATURE 28
2.7 IDENTIFICATION OF KAVAIN AND ITS METABOLITES IN HUMAN SAMPLES 30
2.7.1 STUDY DESIGN 30
2.7.1.1 Guide the strategy of the metabolism study 31
2.7.1.2 The experiment trial using the GC/MS method 31
2.7.1.3 The experiment trhe HPLC-DAD method 31
2.7.2 MATERIALS AND CHEMICALS 32
2.7.3 PREPARATION OF STANDARDS
2.7.3.1 Stock solutions of the reference substances 32
2.7.3.2 Internal standards for GC/MS, HPLC and LC/MS analyses 32
2.7.4 BUFFERS 32
2.7.5 DETERMINATION OF KAVAIN AND ITS METABOLITES IN BLOOD AND URINE USING THE GC/MS
METHOD 33
2.7.5.1 Selected Ion Monitoring mode (SIM) 33
2.7.5.2 Method validation 33
2.7.5.3 Proof of glucuronided kavain metabolites in blood, serum and urine 34
2.7.6 DETERMINATION OF KAVAIN AND ITS METABOLITES IN HUMAN BLOOD, SERUM AND URINE
USING THE HPLC-DAD METHOD 34
2.7.6.1 Method validation 34
2.7.6.2 Proof of glucuronided and sulfateted kavain metabolites in blood, serum and urine 35
2.7.6.3 Instrumentation used for High performance liquid chromatography 35
2.8 RETENTION TIMES (RT), MASS AND UV SPECTRA OF KAVAIN AND ITS FOUR METABOLITES 36
2.8.1 GC EI/MS METHOD 36
2.8.1.1 GC/MS Method validation 39
2.8.2 HPLC-DAD METHOD 41
2.8.2.1 HPLC-DAD method validation 42
2.8.3 ENZYMATIC CLEAVAGE OF THE GLUCURONIDE AND SULFATE OF HYDROXYLATED KAVAIN
METABOLITES 44
3 RESULTS 47
3.1 KAVAIN METABOLISM BY MEANS OF HEP-G2 CELL CULTURES 47
3.2 METABOLISM OF KAVAIN IN HUMAN 51
3.2.1 DETERMINATION OF KAVAIN AND ITS METABOLITES IN URINE AND BLOOD SAMPLES BY GC/MS
51
3.2.1.1 Determination of kavain and its metabolites in urine samples 52
3.2.1.2 Determination of kavas metabolites in blood samples 57
3.2.2 DETERMINATION OF KAVAIN AND ITS METABOLITES IN URINE AND BLOOD SAMPLES USING
HPLC-DAD 59
3.2.2.1 Determination of kavain and its metabolites in urine using the HPLC-DAD method 59
3.2.2.2 Determination of kavas metabolites in serum and blood using the HPLC-DAD
method 62
3.3 APPLICATION OF THE LC/MS METHOD FOR THE DETERMINATION OF KAVAIN URINARY
METABOLITES 67
3.3.1 DETECTION OF KAVAIN AND ITS METABOLITES IN URINE BY LC/MS 67
3.3.2 DETECTIS FOUR MAIN METABOLITES IN URINE SAMPLES AFTER A SINGLE
ORAL DOSE OF 800 MG KAVAIN 71
3.4 KINETICS OF 12-HYDROXYKAVAIN 72
3.4.1 KINETIC OF 12-HYDROXYKAVAIN IN SERUM 73
3.4.2 KINETIC OF 12-HYDROXYKAVAIN IN BLOOD 74
3.4.3 RENAL EXCRETION DATA OF 12-HYDROXYKAVAIN 75
4 DISCUSSION 77
4.1 ANALYTICAL METHODS 77
4.2 KAVAIN METABOLISM BY MEANS OF HEP-G2 CELL LINES 78
4.3 KAVAIN METABOLISM IN HUMAN 80
5 CONCLUSION 91
6 SUMMARY 92
7 ZUSAMMENFASSUNG: 96
8 REFERENCES 99
Abbreviations
Amu Atomic massunit
APCI Atmospheric Pressure Chemical Ionization
AUC_inf Area Under the Concentration-time-curve (extrapolated to infinity)
C last Concentration at T last
C max Maximal Concentration
CI Chemical Ionization
CID Collision Induced Dissociati
Cl_F Apparent Clearance
Cl renal Renal Clearance
CPS Cycle PerSecond
CV Coefficient of Variation
DAD Diode Array Detector
DMSO Dimethylsulfoxide
E. coli Escherichia coli
EI Electron Impact
ESI Electron Spray Ionization
ESI/CID Electron Spray Ionization / Collision Induced Dissociation
GC/FID Gas Chromatography Flam Ionized Detector
GC/MS Gas Chromatography Mass Spectrometry
GC/PND Gas Chromatography Phosphorous-Nitrogen Detector
Hep-G2 Human hepatocellular carcinoma
H. pomatia Helix pomatia
HPLC High Performance Liquid Chromatography
LC Liquid Chromatography
LOD Limit of Detection
m/z Mass to charge ratio
MRT Mean Residence Time
MS Mass Spectrometry
MS/MS Tandem- Mass Spectrometry
MSTFA N-methyl-N-trimethylsilyltrifluoro acetamide
OR Orifice Voltag
Q1-scan Single quadrupole mode
rpm Revolution per minute
RT retention Time
SD Standard Deviation
SIM Selected Ion Monitoring
SPE Solid Phase Extraction
T lag Lag time before onset of kinetics
T last Time of last data point
T max Time of maximal concentration
T Half-life during terminal slope 50
TMAH Tetramethyl ammonium hydroxide
UDP Uridine phosphate
UV Ultra Violet
Vz_F Apparent volume of distribution
λ_z Rate constant of terminal-slope
1 Introduction
1.1 Kava-Kava History
Kavain is one of the main active components of the rhizomes and roots of Piper
methysticum G. Forst. (meaning intoxicating or narcotic pepper, family Piperaceae)
[Kaul and Joshi 2001]. Common names are kava-kava, awa, hereafter referred to as
kava. It is a perennial shrub resembling bamboo [Kaul and Joshi 2001, Czygan and
Hiller 2001, Hölzl et al. 1994, Hänsel 1996 and Singh 1992 ].
Piper methysticum belongs to the most important harvest in its area of circulation e.
g. the islands of the South Pacific such as Oceania and is cultivated with
considerable effort. The rhizomes and roots of the kava plant are being pounded or
chewed and doused with coconut milk or cold water.
The origins of kava usage in Oceania are unknown. Kava drinking itself is much older
than any written history of this part of the world. Kava is an old age drink that was the
beverage of choice for the royal families of the South Pacific. Believed to originate
from Melanesia, kava grows abundantly in the sun-drenched islands of Polynesia.
The kava plant is not spread by seed, but by the cutting of cultivates which are
transported and replanted by humans.
Kava has been used in these cultures for a variety of disorders, some based on real
effects and others on mere hearsay. The past two decades of investigation on
kavalactones, which are claimed to be the active principles of the herb, have
revealed anticonvulsive, analgesic, anxiolytic and centrally acting muscle relaxant
activities [Kaul and Joshi 2001]. Kava, predominantly in form of ethanolic extracts, is
also being prepared as pharmaceutical products. While extracts of Piper methysticum
contain only the l-form of kavain, the synthetic preparations of kavain as
pharmaceutical product are distributed as two enantiomers [Sauer and Hänsel 1967].
1.2 Recreational use of kava beverages
Kava has recently become a drug of abuse amongst some of the aboriginal
communities in Australia where kava is imported mainly from Fiji and Vanuatu.
1Aqueous extraction of the commercially dried plant material is used for the
preparation of kava beverage [Barguil et al. 2002 and Cabalion et al. 2003]. It is
abused due to its sedative and relaxation properties.
The main requirements for beverage preparation are the kava stock, bowl, cup,
strainer and water. Depending on the nature of the occasion, kava would be in the
form of fine roots, or rhizomes and stems, which are then reduced to fine particles.
Alternatively commercially prepared powder may be used. Chewing is the other
method for the preparation of kava. Chewing was normally done by young men or
women. Due to kava local anaesthetics effects in mouth, the chewers had to have
good, strong teeth and jaws, a clean mouth, and they had to be free of ailments e. g.
coughs, colds and sores [Singh 1992].
Nowadays, for instance in New Caledonian kava-bars, kava is prepared by crushing
the dry roots of Piper methysticum in tap water in a basin. It is then filtered with a
tissue or a sock before drinking [Barguil et al. 2002].
Acute kava misuse leads to reversible anaesthesia of the mouth and skin, euphoria,
sedation, muscle weakness, ataxia and eventually intoxication [Alexander 1985,
Alexander et al. 1987, Cawte 1985, Gajdusek 1979, Frater 1976].
1.3 Medicinal use of kava
In many parts of the Pacific, it was generally thought that kava judiciously had a
beneficial health effect. Kava was used for many medicinal purposes e. g. to soothe
the nerves, to induce relaxation and sleep or to counteract fatigue. Kava drinkers
believe kava to restore strength, to soothe stomach pains, and to cure ailments such
as boils. In addition to drinking the pounded root, some people use kava leaves.
Fumigation with the leaves is believed to treat general illnesses. Macerated kava as
well as external application of the masticated kava stump are other methods of cure,
although drinking it in the traditional way is the most popular method of cure.
Kava was extensively used in Germany before World War I in the manufacture of
certain drugs and medicines [Singh 1992]. Kava was used in Europe before World
War I as a treatment for gonorrhoea, cystitis and gout. Kava was also used as
hypnotic, sedative, local anaesthetic, spasmolytic, smooth muscle relaxant, analgesic
and antimycotic [Singh 1992, Kinzler et al. 1991].
2